The scope of the proposed project encompasses both in vitro and in vivo studies designed to elucidate further the endocrine regulation of gonadotropin receptors in ovarian cells. Based upon previous studies in this laboratory, the actions of androgen and human chorionic gonadotropin (hCG) upon ovarian granulosa cell receptors for luteinizing hormone will be concentrated in the following areas: 1) the role of androgen in ovarian physiology, specifically as it relates to the effect of pre-ovulatory antiandrogen treatment upon subsequent ovarian physiology, luteal function in particular. 2) mechanisms by which hCG increases the number of its own receptor binding sites in vitro, and 3) the relationship of the action of other endocrine factors, such as androgen, to hCG-dependent binding. These studies should provide heretofore unavailable information concerning the regulation of ovarian function at the level of the target cell.